The present invention relates to a dual-rod cigarette manufacturing machine.
In particular, the present invention relates to the so-called shaving devices which, on such a machine, operate on the shredded tobacco beads prior to their being wrapped into so-called continuous cigarette rods.
Said machine, as described in U.S. Pat. No. 4,336,812 filed by the present Applicant, provides for forming two tobacco beads by accumulating single tobacco particles on the underside of respective supports consisting of parallel suction type conveyor belts.
As each tobacco bead is fed on the respective conveyor belt to cigarette forming means, it is subjected to a so-called shaving operation for substantially evening off its thickness.
On single-rod cigarette manufacturing machines, the so-called shavers by which this is done consist of two identical coplanar disks, mounted on vertical counter-rotating shafts, and having a circumference equal to a multiple of the cigarette length. Said disks are provided with cutting edges, and arranged tangent to each other along the path of the tobacco bead.
Shaving devices of the aforementioned type are too cumbersome for insertion on dual-rod cigarette manufacturing machines, on which the tobacco beads on the respective conveyors travel extremely close together, said distance being imposed by machine design and allowing of no adjustment. That is to say, if a shaving device of the aforementioned type were to be assigned to each tobacco bead, the disk inserted between the two conveyors would interfere with the second bead, thus preventing it from being fed to the cigarette forming means.
As described in U.S. Pat. No. 4,304,243 filed by the present Applicant, the shaving devices on dual-rod cigarette manufacturing machines therefore consist of pairs of identical truncated-cone disks mounted on inclined, downward-converging shafts. Said disks are arranged with the respective cutting edges on the wider end tangent to each other, and with their generating line aligned with the path of the respective tobacco bead. As such, the disks of each shaving device slope downwards from the point of contact with the respective tobacco bead, thus preventing the disk facing the second bead from interfering with the same.
Truncated-cone disks of the aforementioned type, however, have been found to pose serious grinding problems as compared with the flat types employed on single-rod cigarette manufacturing machines.